Press system

ABSTRACT

A press system capable of achieving improvement in production rate is provided. A controller has a slide driven upward and downward based on a prescribed press motion. A position of the slide where a workpiece can be transported without interfering with an upper die is defined as a feed-allowable height. A stand-by height is higher than the feed-allowable height and located at a highest position in the press motion. The controller also has the work transported while the slide is moving between the feed-allowable height and the stand-by height.

TECHNICAL FIELD

The present invention relates to a press system.

BACKGROUND ART

For example, Japanese Patent Laying-Open No. 2013-184222 (PTL 1)discloses a method of setting a rotary motion at the time when acrankshaft is rotated by a servo motor in a conventional press.

CITATION LIST Patent Literature

PTL 1: Japanese Patent Laying-Open No. 2013-184222

SUMMARY OF INVENTION Technical Problem

In a conventional servo press, an operation of a slide in a pendularmotion and an operation of a feeder are alternately performed. The servopress has been demanded to achieve a further improved production rate.

An object of the present invention is to provide a press system capableof achieving an improved production rate.

Solution to Problem

In a conventional servo press, an approach to improvement in productionrate in a pendular motion by minimizing a distance of travel of a slideby setting a lower limit position where a workpiece can be transportedwithout interfering with a die as a slide stop position has beenadopted. The present inventors have found during studies about furtherimprovement in production rate of the servo press that improvement inproduction rate can be achieved by increasing a distance of travel ofthe slide by shifting the slide stop position upward, and made thepresent invention as below.

A press system according to the present invention includes a pressportion, a transportation portion, and a controller. The press portionincludes an electric motor, an eccentric mechanism, a slide, and abolster. The eccentric mechanism converts a rotary motion by theelectric motor into an upward and downward motion. An upper die can beattached to the slide and the slide is driven upward and downward withthe eccentric mechanism being interposed. A lower die can be attached tothe bolster. The press portion is configured to press work a workpieceby upward and downward movement of the slide with respect to thebolster. The transportation portion is configured to transport theworkpiece. The controller is configured to control the press portion andthe transportation portion. The controller is configured to have theslide driven upward and downward based on a prescribed press motion. Aposition of the slide where the workpiece can be transported withoutinterfering with the upper die is defined as a feed-allowable height,and a position higher than the feed-allowable height and highest in thepress motion is defined as a stand-by height. The controller is alsoconfigured to have the workpiece transported while the slide is movingbetween the feed-allowable height and the stand-by height.

Advantageous Effects of Invention

According to the press system in the present invention, a productionrate can be improved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a construction of a press system basedon an embodiment.

FIG. 2 is a perspective view of a press apparatus based on theembodiment.

FIG. 3 is a lateral cross-sectional view showing a main portion of thepress apparatus.

FIG. 4 is a plan view of a partial cross-section showing another mainportion of the press apparatus.

FIG. 5 is a diagram illustrating overview of a drive system of the presssystem based on the embodiment.

FIG. 6 is a functional block diagram of a CPU based on the embodiment.

FIG. 7 is a schematic diagram showing arrangement of a die and aworkpiece when a slide is located at a feed-allowable height.

FIG. 8 is a schematic diagram showing arrangement of the die and theworkpiece when the slide is located at a touch position.

FIG. 9 is a schematic diagram showing arrangement of the die and theworkpiece when the slide is located at a work end position.

FIG. 10 is a first diagram illustrating an angle of rotation of a mainshaft corresponding to each position representing a slide positionparameter.

FIG. 11 is a second diagram illustrating an angle of rotation of themain shaft corresponding to each position representing a slide positionparameter.

FIG. 12 is a flowchart illustrating generation of a motion in the presssystem based on the embodiment.

FIG. 13 is a diagram showing a press motion and a feeder motiongenerated by the press system based on the embodiment.

FIG. 14 is a diagram showing an approach to setting of a monitoringposition.

DESCRIPTION OF EMBODIMENTS

The present embodiment will be described in detail with reference to thedrawings. The same or corresponding elements in the drawings have thesame reference characters allotted and description thereof will not berepeated.

The present example relates to a press apparatus and describes a forwardfeed press apparatus by way of example.

<Overall Construction>

FIG. 1 is a diagram illustrating a construction of a press system basedon an embodiment. As shown in FIG. 1, the press system includes anuncoiler 100, a leveler feeder (a transportation portion) 200, a pressapparatus (a press portion) 10, and a conveyor 120.

A coil material (a strip plate) is wound around uncoiler 100. In thepresent embodiment, press working of the coil material as a workpiece(material) will be described. The coil material unwound from uncoiler100 is transported to press apparatus 10 by leveler feeder 200.

Leveler feeder 200 adjusts a position of a feed height of the coilmaterial transported from uncoiler 100 to press apparatus 10 andtransports the coil material to press apparatus 10 under an operationcondition (a feeder motion) in a set direction of transportation.

Press apparatus 10 press works the coil material transported fromleveler feeder 200.

Conveyor 120 transports the workpiece formed by press working by pressapparatus 10. Conveyor 120 can also transport the formed workpiece, forexample, to a next press apparatus.

Components in the press system are in synchronization with one another,and a series of operations is sequentially and successively performed.The coil material is transported from uncoiler 100 via leveler feeder200 to press apparatus 10. Then, press apparatus 10 performs pressworking, and the worked workpiece is transported by conveyor 120. Aseries of processes above is repeated.

The above construction of the press system is by way of example andlimitation thereto is not particularly intended.

Leveler feeder 200 is operated in accordance with an instruction frompress apparatus 10. In this connection, a controller configured tocontrol leveler feeder 200 is provided in press apparatus 10.

Though the present example describes a construction in which thecontroller configured to control leveler feeder 200 is provided in pressapparatus 10, limitation thereto is not intended, and for example, acontroller configured to control press apparatus 10 may be provided on aside of leveler feeder 200. A controller configured to control pressapparatus 10 and leveler feeder 200 may be arranged at a positiondifferent from press apparatus 10 and leveler feeder 200 to remotelycontrol press apparatus 10 and leveler feeder 200. The embodimentdescribes an example in which a single controller controls both ofleveler feeder 200 and press apparatus 10.

<Press Apparatus>

FIG. 2 is a perspective view of press apparatus 10 based on theembodiment.

FIG. 2 shows a forward feed press apparatus without a plunger by way ofexample.

Press apparatus 10 includes a main body frame 2, a slide 20, a bed 4, abolster 5, a control panel 6, and a controller 40.

Slide 20 is supported in a substantially central portion of main bodyframe 2 of press apparatus 10 as being vertically movable. Bolster 5attached onto bed 4 is arranged under slide 20. Controller 40 isprovided laterally to main body frame 2. Control panel 6 connected tocontroller 40 is provided laterally to main body frame 2 and in front ofcontroller 40.

An upper die of dice for working a workpiece is removably attached to alower surface of slide 20. A lower die of the dice for working aworkpiece is removably attached to an upper surface of bolster 5. Aprescribed workpiece corresponding to the dice is placed on the lowerdie, the upper die is lowered together with slide 20, and the workpieceis press worked as being sandwiched between the upper die and the lowerdie.

A remote controller (remote control unit) 70 provided to communicatewith a main body of press apparatus 10 and to allow external remotecontrol is provided. An operator (a person responsible for operation)can perform various setting operations by operating remote controller70. Remote controller 70 can communicate with controller 40 to operatepress apparatus 10 in accordance with an instruction therefrom.

The present example shows that remote controller 70 is provided with anup button 72 and a down button 74 for vertically operating slide 20 andan enter button 76.

Control panel 6 is provided to input various types of data necessary forcontrolling press apparatus 10, and includes a switch and a numerickeypad for inputting data and a display configured to show a settingscreen and data output from press apparatus 10.

Such a programmable display that a transparent touch switch panel isattached to a front surface of a graphic display such as a liquidcrystal display or a plasma display is adopted as a display.

Control panel 6 may include a data input device which receives input ofdata from an external storage medium such as an integrated circuit (IC)card where data set in advance is stored or a communication device whichtransmits and receives data wirelessly or through a communication line.

Though the present example describes a construction in which both ofcontrol panel 6 and remote controller 70 are provided for pressapparatus 10, the construction of press apparatus 10 is by way ofexample and limitation thereto is not intended. For example, only one ofcontrol panel 6 and remote controller 70 may be provided for pressapparatus 10.

FIG. 3 is a lateral cross-sectional view showing a main portion of pressapparatus 10. As shown in FIG. 3, press apparatus 10 is implemented by aservo press.

Press apparatus 10 includes a servo motor 121, a spherical hole 33A, ascrew shaft 37, a spherical portion 37A, a thread portion 37B, and aconnecting rod main body 38. Press apparatus 10 further includes afemale thread portion 38A, a connecting rod 39, a main shaft 110, aneccentric portion 110A, a side frame 111, bearing portions 112 to 114, amain gear 115, a power transmission shaft 116, a transmission gear 116A,bearing portions 117 and 118, and a pulley 119.

In press apparatus 10, servo motor 121 drives slide 20. Servo motor 121represents one example of an electric motor. In spherical hole 33Aprovided in an upper portion of slide 20, spherical portion 37A providedat a lower end of screw shaft 37 for adjusting a die height is rotatablyinserted so as not to come off. Spherical hole 33A and spherical portion37A make up a spherical joint. Thread portion 37B of screw shaft 37 isexposed upward through slide 20, and screwed to female thread portion38A of connecting rod main body 38 provided above screw shaft 37. Screwshaft 37 and connecting rod main body 38 make up extendable connectingrod 39.

The die height refers to a distance from a lower surface of slide 20 atthe time when slide 20 is arranged at a bottom dead center to an uppersurface of bolster 5.

An upper portion of connecting rod 39 is rotatably coupled to eccentricportion 110A like a crank provided in main shaft 110. Main shaft 110 ismovably supported by bearing portions 112, 113, and 114 located at threefront and rear locations between a pair of left and right thick sideframes 111 which form main body frame 2. Main gear 115 is attached to arear portion of main shaft 110.

Main gear 115 is meshed with transmission gear 116A of powertransmission shaft 116 provided below. Power transmission shaft 116 ismovably supported by bearing portions 117 and 118 located at two frontand rear locations between side frames 111. Power transmission shaft 116has a rear end attached to driven pulley 119. Pulley 119 is driven byservo motor 121 arranged below.

Press apparatus 10 further includes a bracket 122, an output shaft 121A,a pulley 123, a belt 124, a bracket 125, a position detector 126, a rod127, a position sensor 128, an auxiliary frame 129, and bolts 131 and132.

Servo motor 121 is supported between side frames 111 with bracket 122substantially in an L shape being interposed. Servo motor 121 has outputshaft 121A projecting along a front-rear direction of press apparatus10, and motive power is transmitted by belt 124 wound around drivingpulley 123 provided on output shaft 121A and driven pulley 119.

A pair of brackets 125 projecting rearward between side frames 111 fromtwo upper and lower locations is attached on a rear surface side ofslide 20. Rod 127 which implements position detector 126 such as alinear scale is attached between upper and lower brackets 125. Rod 127is provided with a scale for detecting a vertical position of slide 20and vertically movably fitted into position sensor 128 similarlyimplementing position detector 126. Position sensor 128 is fixed toauxiliary frame 129 provided in one side frame 111.

Auxiliary frame 129 is formed in a vertically elongated manner. Theauxiliary frame has a lower portion attached to side frame 111 by bolt131 and an upper portion vertically slidably supported by bolt 132inserted in a vertically elongated hole. Auxiliary frame 129 has thusonly any one side (a lower side in the present embodiment) of upper andlower sides fixed to side frame 111 and has the other side verticallymovably supported. Therefore, the auxiliary frame is not affected bycontraction and extension caused by variation in temperature of sideframe 111. Position sensor 128 can thus accurately detect a slideposition and a die height position without being affected by suchcontraction and extension of side frame 111.

A slide position of slide 20 and a die height are adjusted by a slideposition adjustment mechanism 133 (FIG. 4) provided in slide 20. FIG. 4is a plan view of a partial cross-section showing another main portionof press apparatus 10.

As shown in FIG. 4, slide position adjustment mechanism 133 isconstituted of a worm wheel 134 attached to an outer circumference ofspherical portion 37A with a pin 37C being interposed, a worm gear 135meshed with worm wheel 134, an input gear 136 attached to an end of wormgear 135, and an induction motor 138 including an output gear 137 (FIG.3) meshed with input gear 136. Induction motor 138 is in a flat shapeshorter in axial length and constructed to be compact. Screw shaft 37can be turned by a rotary motion of induction motor 138 with worm wheel134 being interposed. A length of screwing between thread portion 37B ofscrew shaft 37 and female thread portion 38A of connecting rod main body38 is thus varied to adjust the slide position of slide 20 and the dieheight.

<Configuration of Drive System of Press System>

FIG. 5 is a diagram illustrating overview of a drive system of the presssystem based on the embodiment.

As shown in FIG. 5, leveler feeder 200 includes a transportation roller63, a servo motor 62, an encoder 64, a feed completion detector 68, anda servo amplifier 60.

Press apparatus 10 includes controller 40, a servo amplifier 66, servomotor 121, an encoder 65, main gear 115, main shaft 110, eccentricportion 110A, slide 20, an upper die 22A, a lower die 22B, and bolster5.

Controller 40 includes a central processing unit (CPU) 42, a memory 44,a communication circuit 46, and an input unit 48.

Communication circuit 46 is provided to be able to communicate withremote controller 70.

CPU 42 outputs a target value to servo amplifier 60. Servo amplifier 60gives a speed instruction to servo motor 62 based on the target value.Transportation roller 63 performs an operation to transport a workpieceW as servo motor 62 is driven. Feed completion detector 68 determineswhether or not an operation to transport workpiece W has been completed.When the feed completion detector detects completion of thetransportation operation and stop of workpiece W, the feed completiondetector outputs a result of detection to CPU 42 as a feed completionsignal.

Encoder 64 outputs a feedback signal based on the number of rotations ofservo motor 62 in accordance with the speed instruction to servoamplifier 60.

Servo amplifier 60 adjusts the number of rotations of servo motor 62 toa value in accordance with the target value by controlling supply ofelectric power to servo motor 62 based on the feedback signal fromencoder 64.

Through the processing, CPU 42 controls a speed of transportation in theoperation to transport workpiece W.

Similarly, CPU 42 outputs a target value to servo amplifier 66. Servoamplifier 66 gives a speed instruction to servo motor 121 based on thetarget value. Main gear 115 drives main shaft 110 as servo motor 121 isdriven. As main shaft 110 is driven, eccentric portion 110A is rotated.Eccentric portion 110A is coupled to slide 20, and slide 20 to whichupper die 22A is attached moves upward and downward in accordance with arotation of eccentric portion 110A. Eccentric portion 110A implements aneccentric mechanism which converts a rotary motion by servo motor 121into an upward and downward motion of slide 20. As slide 20 is drivenupward and downward and lowered to a position of the bottom dead centerunder an operation condition (press motion) in the set upward anddownward direction, press working of workpiece W transported to aposition between upper die 22A and lower die 22B is performed.

Upper die 22A is a movable die which is attached to slide 20 and isreciprocatively vertically moved integrally with slide 20 with upwardand downward movement of slide 20. Lower die 22B is a fixed die attachedto bolster 5 and placed and fixed onto bolster 5. As slide 20 movesupward and downward with respect to bolster 5, workpiece W is sandwichedbetween upper die 22A and lower die 22B and press worked.

Encoder 65 outputs a feedback signal based on the number of rotations ofservo motor 121 in accordance with a speed instruction to servoamplifier 66.

Servo amplifier 66 adjusts the number of rotations of servo motor 121 toa value in accordance with the target value by controlling supply ofelectric power to servo motor 121 based on the feedback signal fromencoder 65.

Through the processing, CPU 42 controls a speed of slide 20 in theupward and downward movement.

CPU 42 based on the embodiment performs processing for synchronizing atransportation operation by leveler feeder 200 (which is also simplyreferred to as a feeder) with the upward and downward movement of slide20 of press apparatus 10 based on control data stored in memory 44.

Specifically, memory 44 stores control data in which upward and downwardmovement of slide 20 is associated with a workpiece transportationoperation by leveler feeder 200.

Input unit 48 accepts input of various parameters. In the presentexample, input unit 48 accepts input of a parameter through controlpanel 6 or remote controller 70. An operator inputs various parametersby operating a switch and a numeric keypad in control panel 6 or eachbutton on remote controller 70. Control panel 6 and remote controller 70implement the operation portion in the embodiment.

A parameter received by input unit 48 includes a slide positionparameter relating to a position of slide 20 in the upward and downwarddirection with respect to bolster 5. A parameter received by input unit48 includes a transportation parameter relating to an operation byleveler feeder 200.

<Generation of Motion>

A method of generating a motion based on the embodiment will now bedescribed.

FIG. 6 is a functional block diagram of CPU 42 based on the embodiment.

As shown in FIG. 6, CPU 42 includes a touch speed generator 51, a pressmotion generator 53, a feeder motion generator 55, a motion synthesizer56, and an execution unit 58.

Each one in the functional block diagram is implemented in coordinationwith each component (such as communication circuit 46) by execution byCPU 42 of a prescribed application program stored in memory 44.

Touch speed generator 51 sets a speed (touch speed) of slide 20 at thetime when slide 20 is lowered and upper die 22A comes in contact withworkpiece W based on a material property and a thickness of workpiece Winput to input unit 48.

Press motion generator 53 automatically generates a press motion basedon a slide position parameter input to input unit 48. The slide positionparameter includes a feed-allowable height, a touch position, and a workend position.

Feeder motion generator 55 automatically generates a feeder motion basedon a transportation parameter input to input unit 48. The transportationparameter includes a feed length.

Motion synthesizer 56 automatically generates a synthesized motion byautomatically synthesizing the press motion generated by press motiongenerator 53 and a feeder motion generated by feeder motion generator55.

The feed-allowable height refers to a lower limit of a position of slide20 where upper die 22A does not interfere with transported workpiece W.FIG. 7 is a schematic diagram showing arrangement of the die andworkpiece W when slide 20 is located at the feed-allowable height. Whenslide 20 is distant from bolster 5 by a distance greater than thefeed-allowable height, workpiece W can be transported withoutinterfering with upper die 22A.

The touch position refers to a position of slide 20 at the time whenupper die 22A comes in contact with workpiece W. FIG. 8 is a schematicdiagram showing arrangement of the die and workpiece W when slide 20 islocated at the touch position. When slide 20 lowered toward bolster 5reaches the touch position, upper die 22A comes in contact withworkpiece W placed on lower die 22B.

The work end position refers to a position of slide 20 at the time pointof end of press working of workpiece W. FIG. 9 is a schematic diagramshowing arrangement of the die and workpiece W when slide 20 is locatedat the work end position. When slide 20 lowered toward bolster 5 reachesthe work end position, press working of workpiece W ends.

The feed length refers to a length of transportation of workpiece W byleveler feeder 200 in the direction of transportation of workpiece Wafter end of press working of workpiece W and before start of next pressworking. A speed of transportation of workpiece W transported by levelerfeeder 200 is referred to as a feed rate. The feed rate is saved inmemory 44. Alternatively, the feed rate may be included in atransportation parameter input to input unit 48.

When press motion generator 53 generates a press motion, an operationmode for maximizing an amount of production per unit time is set.Furthermore, a production rate (unit: shot per minute (SPM)) is set.

The operation mode includes a rotary motion, a reverse motion, and apendular motion.

The rotary motion refers to an operation mode in which eccentric portion110A (FIG. 3) is rotated in one direction to drive slide 20 in onecycle.

The reverse motion refers to an operation mode in which slide 20 isreversely driven between a down stroke and an up stroke between twoangles of rotation corresponding to prescribed lower limit position andupper limit position set between angles of rotation of eccentric portion110A corresponding to the top dead center and the bottom dead center ofslide 20.

The pendular motion refers to an operation mode in which slide 20 isreciprocatively driven across the bottom dead center by setting as twoupper limit positions, two angles of rotation distant by a prescribedangle in a direction of forward rotation and a direction of reverserotation from a bottom dead center angle of rotation of eccentricportion 110A corresponding to the bottom dead center of slide 20 androtationally driving the slide in one direction from one upper limitposition across the bottom dead center angle of rotation to the otherupper limit position.

Execution unit 58 controls a transportation operation by leveler feeder200 and press working by press apparatus 10 based on a synthesizedmotion generated by motion synthesizer 56. Specifically, execution unit58 outputs a target value for driving servo motors 62 and 121 to servoamplifiers 60 and 66 based on the synthesized motion, and performssynchronization processing for synchronizing the press motion and thefeeder motion with each other.

FIG. 10 is a first diagram illustrating an angle of rotation of mainshaft 110 corresponding to each position representing a slide positionparameter. FIG. 10 shows angles of rotation of main shaft 110corresponding to a top dead center TDC, a bottom dead center BDC, astand-by height P0, a monitoring position Pa, a feed-allowable heightP1, a touch position P2, a work end position P3, a jump preventionheight P4, a feed-allowable height P5, and a stand-by height P6 of slide20. FIG. 10 shows each position representing a slide position parameterwhen main shaft 110 is rotated clockwise in the figure.

The operation mode of slide 20 is set to the pendular motion in whichthe slide is reciprocatively driven across bottom dead center BDC withstand-by heights P0 and P6 being defined as upper limit positions. Slide20 starts lowering from stand-by height P0, sequentially passesmonitoring position Pa, feed-allowable height P1, touch position P2, andwork end position P3, reaches bottom dead center BDC, moves upward frombottom dead center BDC, sequentially passes jump prevention height P4and feed-allowable height P5, moves to stand-by height P6, and stops.Since stand-by heights P0 and P6 are located at positions lower than topdead center TDC, slide 20 never passes top dead center TDC.

As shown in FIG. 10, stand-by height P0 is located at a position higherthan feed-allowable height P1. Stand-by height P6 is located at aposition higher than feed-allowable height P5. Stand-by heights P0 andP6 are located at a highest position in a press motion. Monitoringposition Pa is set at a position higher than feed-allowable height P1and lower than stand-by height P0 in the upward and downward directionof slide 20.

Work end position P3 is set as a position higher than bottom dead centerBDC. Lowered slide 20 passes work end position P3 before reaching bottomdead center BDC.

Jump prevention height P4 is set as a position higher than bottom deadcenter BDC. Slide 20 starts moving upward after it passes bottom deadcenter BDC, and passes jump prevention height P4. In order to preventwobble of workpiece W between upper die 22A and lower die 22B at thetime when upper die 22A is raised after end of press working ofworkpiece W, a speed of slide 20 while it is moved from work endposition P3 to jump prevention height P4 is set to be low.

A different position of jump prevention height P4 can be set for eachcondition of a material property, a thickness, and a method of workingof workpiece W. Set jump prevention height P4 is saved in memory 44(FIG. 5). When jump prevention height P4 corresponding to workpiece W tobe press worked has not been saved in memory 44 at the time of change inmaterial property, thickness, or method of working of workpiece W, jumpprevention height P4 is set by making trials a plurality of times beforestarting working.

FIG. 11 is a second diagram illustrating an angle of rotation of mainshaft 110 corresponding to each position representing a slide positionparameter. FIG. 11 shows angles of rotation of main shaft 110corresponding to top dead center TDC, bottom dead center BDC, stand-byheight P0, monitoring position Pa, feed-allowable height P1, touchposition P2, work end position P3, jump prevention height P4,feed-allowable height P5, and stand-by height P6 of slide 20 as in FIG.10. FIG. 11 shows each position representing a slide position parameterwhen main shaft 110 is rotated counterclockwise in the figure.

Stand-by height P0 shown in FIG. 11 is a position the same as stand-byheight P6 which represents a stop position of slide 20 shown in FIG. 10.Monitoring position Pa, feed-allowable height P1, touch position P2,work end position P3, jump prevention height P4, and feed-allowableheight P5 shown in FIGS. 10 and 11 are set in line symmetry with respectto a straight line which passes through top dead center TDC and bottomdead center BDC in FIGS. 10 and 11. Stand-by height P6 shown in FIG. 11is a position the same as stand-by height P0 which represents a movementstart position of slide 20 shown in FIG. 10. Slide 20 starts loweringfrom stand-by height P0, sequentially passes monitoring position Pa,feed-allowable height P1, touch position P2, and work end position P3,reaches bottom dead center BDC, starts moving upward from bottom deadcenter BDC, sequentially passes jump prevention height P4 andfeed-allowable height P5, moves to stand-by height P6, and stops.

FIG. 12 is a flowchart illustrating generation of a motion in the presssystem based on the embodiment.

As shown in FIG. 12, initially, in step S1, various parameters are inputto input unit 48. Specifically, an operator inputs parameters necessaryfor generating a motion by operating control panel 6 or remotecontroller 70 (FIG. 2).

Then, in step S2, a touch speed is set. Specifically, touch speedgenerator 51 sets a touch speed by referring to a touch speed table foreach material property of workpiece W stored in memory 44 (FIG. 5) ofcontroller 40, based on input material property and thickness ofworkpiece W.

Then, in step S3, a feeder motion is generated. Specifically, feedermotion generator 55 generates a feeder motion based on input feed lengthand feed rate.

FIG. 13 is a diagram showing a press motion and a feeder motiongenerated by the press system based on the embodiment. The abscissa inthe graph in FIG. 13 (A) represents time and the ordinate represents anangular speed ω of main shaft 110 based on rotational drive by servomotor 121. An angular speed (max represents a value set as a maximumvalue of the angular speed of main shaft 110. An angular speed ω1represents an angular speed of main shaft 110 corresponding to a touchspeed set in step S2. As main shaft 110 rotates at angular speed ω1, alowering speed of slide 20 is set to a touch speed. In FIG. 13 (A),stand-by height P0, monitoring position Pa, feed-allowable height P1,touch position P2, work end position P3, jump prevention height P4,feed-allowable height P5, and stand-by height P6 are plotted. Theabscissa in the graph in FIG. 13 (B) represents time and the ordinaterepresents a speed of transportation v of workpiece W.

As shown in FIG. 13 (B), the transportation speed is increased up to theset feed rate at a prescribed acceleration from a state that workpiece Wremains stopped (speed of transportation v=0). After reaching the feedrate, transportation of workpiece W at the set feed rate is continued toa position where the speed can be lowered by deceleration at aprescribed acceleration to speed of transportation v=0 at the time pointof transportation of workpiece W by a set transportation length. Aprescribed value of an acceleration at the time of increase or decreasein transportation speed is saved in memory 44.

Workpiece W is decelerated from the set feed rate at a prescribedacceleration. Speed of transportation v=0 is achieved at the time pointof transportation of workpiece W by the set transportation length.Transportation of workpiece W is thus completed. The feeder motion isgenerated as set forth above.

Referring back to FIG. 12, in step S4, a press motion is generated.Specifically, press motion generator 53 generates a press motion basedon the input feed-allowable height (P1), touch position (P2), and workend position (P3) and the touch speed set in step S2.

As shown in FIG. 13 (A), stand-by height P0 refers to a position whereslide 20 remains stopped, and hence angular speed ω of main shaft 110 atstand-by height P0 is zero. Stand-by height P0 is set as a position fromwhich the main shaft can be accelerated to maximum angular speed ωmax atan angle of rotation corresponding to feed-allowable height P1 by beingaccelerated at a prescribed acceleration.

Slide 20 starts lowering from stand-by height P0 toward bottom deadcenter BDC, and is accelerated at a prescribed acceleration until mainshaft 110 reaches maximum angular speed ωmax. Main shaft 110 reaches itsmaximum angular speed ωmax when slide 20 passes feed-allowable heightP1. Slide 20 passes feed-allowable height P1 at the maximum speed. Mainshaft 110 completes acceleration before slide 20 passes feed-allowableheight P1 as slide 20 is lowered.

After maximum angular speed ωmax is reached, rotation of main shaft 110at maximum angular speed ωmax is continued to a position where the speedcan be lowered by deceleration at a prescribed acceleration to touchspeed ω1 at an angle of rotation corresponding to touch position P2.Prescribed values of maximum angular speed (max of main shaft 110 and anacceleration at the time of acceleration and deceleration are saved inmemory 44.

Main shaft 110 is decelerated from maximum angular speed ωmax androtated at angular speed ω1 at the time point when slide 20 reachestouch position P2. Thereafter, main shaft 110 is rotated at equalangular speed ω1 until slide 20 reaches work end position P3. Slide 20is thus lowered at the touch speed from touch position P2 to work endposition P3.

When slide 20 reaches work end position P3, main shaft 110 (and slide20) starts acceleration. While slide 20 is moving between work endposition P3 and jump prevention height P4, in order to prevent wobble ofworkpiece W, slide 20 is moved at a speed slightly higher than the touchspeed and main shaft 110 is rotated at a speed slightly higher thanangular speed ω1.

When slide 20 reaches jump prevention height P4, main shaft 110 is againaccelerated at a prescribed acceleration until maximum angular speedωmax is reached. After maximum speed ωmax is reached, rotation of mainshaft 110 at maximum angular speed ωmax is continued until slide 20reaches feed-allowable height P5. Slide 20 passes feed-allowable heightP5 at the maximum speed.

As slide 20 passes feed-allowable height P5, main shaft 110 isdecelerated at a prescribed acceleration from maximum angular speedωmax. Main shaft 110 starts deceleration after it passes feed-allowableheight P5 as slide 20 is moved upward. Main shaft 110 stops rotation atthe time point when slide 20 reaches stand-by height P6. Slide 20 stopsat a position at stand-by height P6. Stand-by height P6 is set as aposition where the main shaft is decelerated to a zero angular speed bydeceleration at a prescribed acceleration from an angle of rotationcorresponding to feed-allowable height P5. The press motion is generatedas set forth above.

Then, in step S5, a synthesized motion is generated. Specifically,motion synthesizer 56 generates a synthesized motion by synthesizing thefeeder motion generated in step S3 and the press motion generated instep S4.

As shown in FIG. 13, after slide 20 passes feed-allowable height P5 atthe highest speed, transportation of workpiece W is started. At the timepoint when slide 20 passes feed-allowable height P5, speed oftransportation v of workpiece W is v=0. At the time point of start oftransportation of workpiece W, slide 20 is moving from feed-allowableheight P5 to stand-by height P6. While slide 20 is being transportedbetween feed-allowable height P5 and stand-by height P6, workpiece W isalso being transported. While slide 20 is decelerated, transportation ofworkpiece W by leveler feeder 200 is started.

Slide 20 which has stopped at stand-by height P6 starts lowering afterlapse of a prescribed time period. Main shaft 110 which has stoppedrotation when slide 20 reached stand-by height P6 starts rotation in areverse direction after lapse of the prescribed time period.

A time period elapsed since start of transportation of workpiece Wasusual until completion of feed in transportation of workpiece W by afeed length at a prescribed acceleration and at a set feed rate isreferred to as a feeder movement time period. Main shaft 110 startsrotation such that slide 20 reaches monitoring position Pa after lapseof a press waiting time (margin) ts since a time point of lapse of thefeeder movement time period. Leveler feeder 200 stops its operationwhile slide 20 is accelerated. Feed of workpiece W has been completedpress waiting time (margin) ts before the time point when slide 20lowered from stand-by height P0 reaches monitoring position Pa higherthan feed-allowable height P1. Feed of workpiece W has been completed bythe time point when slide 20 reaches feed-allowable height P1.

The synthesized motion in which interference between an operation totransport workpiece W and upward and downward movement of upper die 22Adoes not occur is thus generated.

An approach to setting of monitoring position Pa will be described. FIG.14 is a diagram showing an approach to setting of monitoring positionPa. The abscissa in the graph in FIGS. 14 (A) and (B) represents time.The ordinate in the graph in FIG. 14 (A) represents a position P ofslide 20. The ordinate in the graph in FIG. 14 (B) represents angularspeed co of main shaft 110 based on rotational drive by servo motor 121.

A solid line in FIG. 14 (A) represents a position of slide 20 when theslide is lowered as being accelerated at a prescribed acceleration untiltime Ta and forced stop of slide 20 is started at time Ta, and a solidline in FIG. 14 (B) represents an angular speed of main shaft 110 whenthe main shaft is rotated as being accelerated at a prescribed angularacceleration until time Ta and forced stop of rotation of main shaft 110is started at time Ta. A dashed line in FIG. 14 (A) represents aposition of slide 20 after time Ta when slide 20 is lowered in a normaloperation, and a dashed line in FIG. 14 (B) represents an angular speedof main shaft 110 after time Ta when main shaft 110 is rotated in anormal operation.

As described above, stand-by height P0 refers to a position where slide20 remains stopped, and hence angular speed co of main shaft 110 atstand-by height P0 is zero. Main shaft 110 is accelerated at aprescribed acceleration so as to reach maximum angular speed co at thetime when slide 20 passes feed-allowable height P1. At time Ta, as shownin FIG. 14 (A), slide 20 reaches monitoring position Pa.

At the time point of time Ta when slide 20 is lowered from stand-byheight P0 and reaches monitoring position Pa, controller 40 determineswhether or not completion of feed of workpiece W has been detected.Controller 40 determines whether or not it has received input of a feedcompletion signal indicating completion of transportation of workpiece Wfrom feed completion detector 68 (FIG. 5) at time Ta a prescribed timeperiod after start of lowering of slide 20 from stand-by height P0.

When completion of feed of workpiece W has not been detected at time Ta,controller 40 forces slide 20 to stop. As shown in FIG. 14 (B), mainshaft 110 is decelerated at a prescribed acceleration after time Ta. Attime Tb, main shaft 110 stops rotation, angular speed ω shown in FIG. 14(B) is set to zero, and slide 20 stops. A stop position Pb where slide20 stops is higher than feed-allowable height P1 as shown in FIG. 14(A).

Monitoring position Pa is thus set such that slide 20 which has startedlowering from stand-by height P0 and reached monitoring position Pa canstart deceleration at monitoring position Pa and stop at stop positionPb higher than feed-allowable height P1 when completion of feed ofworkpiece W has not been detected.

Referring back to FIG. 12, in step S6, workpiece W is worked inaccordance with the generated synthesized motion. Execution unit 58 haspress working of workpiece W performed based on the generatedsynthesized motion.

Then, in step S7, whether or not a result of working of workpiece Wbased on the synthesized motion generated in step S5 is appropriate isdetermined. For example, torque required for rotation of main shaft 110is calculated based on a current value of servo motor 121, and when thetorque exceeds an allowable value, the result of working is determinedas inappropriate. Alternatively, for example, vibration generated duringworking is determined, and when vibration exceeds an allowable value,the result of working is determined as inappropriate. The allowablevalue of torque or vibration has been saved in memory 44.

When the result of working is determined as inappropriate (NO in stepS7), the synthesized motion is modified in step S8. For example, a speedother than the speed during press working (that is, the touch speed ofslide 20 (angular speed ω1 of main shaft 110)) is modified to be lower.

After the synthesized motion is modified, the process returns to stepS6, where workpiece W is worked in accordance with the modifiedsynthesized motion. In succession, in step S7, whether or not the resultof working of workpiece W based on the modified synthesized motion isappropriate is determined.

When the result of working is determined as appropriate (YES in stepS7), the process proceeds to step S9, where the synthesized motion issaved in memory 44.

In step S10, the result is output. Values input as a slide positionparameter and a transportation parameter and a set and calculated valuedetermined with automatic generation of a motion are shown on thedisplay of control panel 6, so that an operator can readily know a stateof operation by the press system by viewing that screen on the display.

Then, the process ends (end).

<Function and Effect>

A function and effect of the present embodiment will now be described.

According to the press system based on the embodiment, as shown in FIGS.10 and 11, stand-by height P0 located at a position higher thanfeed-allowable height P1 is set and stand-by height P6 located at aposition higher than feed-allowable height P5 is set. As shown in FIG.13, transportation of workpiece W is started while slide 20 is movingbetween feed-allowable height P5 and stand-by height P6, andtransportation thereof is completed while slide 20 is moving betweenstand-by height P0 and feed-allowable height P1. Transportation ofworkpiece W and movement of slide 20 overlap in time.

When slide 20 is stopped at feed-allowable height P1, P5, the speed ofslide 20 should be zero at feed-allowable height P1, P5. By setting aposition where slide 20 is to be stopped at stand-by height P0, P6higher than feed-allowable height P1, P5 instead of feed-allowableheight P1, P5, slide 20 is moved at a speed higher than zero at the timepoint of passage by feed-allowable height P1, P5. Thus, a time periodrequired for slide 20 to lower from feed-allowable height P1 and a timeperiod until slide 20 is moved upward and reaches feed-allowable heightP5 can be shortened. More specifically, a time period for slide 20 to bemoved from feed-allowable height P1 across bottom dead center BDC tofeed-allowable height P5 can be shortened.

Before slide 20 passes feed-allowable height P1 and after slide 20passes feed-allowable height P5, workpiece W can be transported withoutinterfering with a die. Since the time period for slide 20 to be movedfrom bottom dead center BDC to feed-allowable height P5 is shortened,timing of start of transportation of workpiece W can be advanced. As thetime period required for one cycle of press working is shortened, aproduction rate of the press system can be improved.

As shown in FIG. 13, main shaft 110 has been decelerated from maximumangular speed ωmax to zero by the time when slide 20 reaches stand-byheight P6 after it passed feed-allowable height P5. Therefore, servomotor 121 has also been decelerated by the time when slide 20 reachesstand-by height P6 after it passed feed-allowable height P5.Transportation of workpiece W by leveler feeder 200 is started duringdeceleration of servo motor 121.

By doing so, a time period of transportation of workpiece W and a timeperiod of movement of slide 20 can reliably overlap with each other.From a point of view of a shorter distance of travel of slide 20,stand-by height P6 is desirably set at a position closer tofeed-allowable height P5. By making such setting that servo motor 121has already been decelerated by the time point of start oftransportation of workpiece W, slide 20 can readily be stopped atstand-by height P6 closer to feed-allowable height P5.

As shown in FIG. 13, deceleration of main shaft 110 is started afterslide 20 passes feed-allowable height P5. Therefore, while slide 20 ismoving upward, deceleration of servo motor 121 is started after slide 20passes feed-allowable height P5. Servo motor 121 has not yet beendecelerated at the time of passage by feed-allowable height P5. Slide 20passes feed-allowable height P5 at the highest speed. By doing so, atime period for slide 20 to be moved from feed-allowable height P1across bottom dead center BDC to feed-allowable height P5 can reliablybe shortened.

As shown in FIG. 13, main shaft 110 has been accelerated from a zeroangular speed to maximum angular speed (max by the time when slide 20reaches feed-allowable height P1 after it starts movement from stand-byheight P0. Therefore, servo motor 121 has also been accelerated whileslide 20 is moving from stand-by height P0 to feed-allowable height P1.Transportation of workpiece W by leveler feeder 200 is completed duringacceleration of servo motor 121.

By doing so, a time period of transportation of workpiece W and a timeperiod of movement of slide 20 can reliably overlap with each other.From a point of view of a shorter distance of travel of slide 20,stand-by height P0 is desirably set at a position closer tofeed-allowable height P1. By making such setting that servo motor 121 isbeing accelerated and the slide is moved at a speed lower than thehighest speed at the time point of completion of feed of workpiece W,slide 20 can readily be lowered from stand-by height P0 closer tofeed-allowable height P1.

As shown in FIG. 13, main shaft 110 has completed acceleration beforeslide 20 passes feed-allowable height P1. Therefore, as slide 20 islowered, acceleration of servo motor 121 has been completed before slide20 passes feed-allowable height P1. By the time point of passage byfeed-allowable height P1, servo motor 121 has reached the highest speed.Slide 20 passes feed-allowable height P1 at the highest speed. By doingso, a time period for slide 20 to be moved from feed-allowable height P1across bottom dead center BDC to feed-allowable height P5 can reliablybe shortened.

As shown in FIG. 14, stand-by height P0 and monitoring position Pa areset such that when completion of feed of workpiece W has not beendetected at the time point when slide 20 lowered from stand-by height P0reaches monitoring position Pa, slide 20 can be stopped at stop positionPb higher than feed-allowable height P1. Even though an abnormalcondition occurs during transportation of workpiece W, interferencebetween workpiece W and a die can thus reliably be avoided.

An example in which the operation mode of slide 20 is set to thependular motion has been described. Without being limited to the examplein which the operation mode is set to the pendular motion, the conceptin the embodiment described above is applicable to an example in whichslide 20 moves upward and downward with respect to bolster 5 by rotatingservo motor 121 alternately in forward and reverse directions duringpress working each time press working of workpiece W is performed. Forexample, the concept of the embodiment described above can be appliedalso to an example in which the operation mode is set to a reversemotion.

The press apparatus is not limited to those of the constructiondescribed in the embodiment, and the press apparatus may be constructedsuch that a plunger and a plunger holder are interposed between theconnecting rod and the slide. An eccentric mechanism may have acrankshaft structure or a drum structure.

It should be understood that the embodiment disclosed herein isillustrative and non-restrictive in every respect. The scope of thepresent invention is defined by the terms of the claims rather than thedescription above and is intended to include any modifications withinthe scope and meaning equivalent to the terms of the claims.

REFERENCE SIGNS LIST

2 main body frame; 4 bed; 5 bolster; 6 control panel; 10 pressapparatus; 20 slide; 22A upper die; 22B lower die; 37 screw shaft; 38connecting rod main body; 39 connecting rod; 40 controller; 42 CPU; 44memory; 46 communication circuit; 48 input unit; 51 touch speedgenerator; 53 press motion generator; 55 feeder motion generator; 56motion synthesizer; 58 execution unit; 60, 66 servo amplifier; 61display; 62, 121 servo motor; 63 transportation roller; 64, 65 encoder;68 feed completion detector; 70 remote controller; 72, 74 button; 76enter button; 100 uncoiler; 110 main shaft; 110A eccentric portion; 115main gear; 200 leveler feeder

1. A press system comprising: a press portion including an electricmotor, an eccentric mechanism configured to convert a rotary motion bythe electric motor into a motion in an upward and downward direction, aslide to which an upper die is attachable, the slide being driven upwardand downward with the eccentric mechanism being interposed, and abolster to which a lower die is attachable, the press portion beingconfigured to press work a workpiece by upward and downward movement ofthe slide with respect to the bolster; a transportation portionconfigured to transport the workpiece; and a controller configured tocontrol the press portion and the transportation portion, the controllerbeing configured to have the slide driven upward and downward based on aprescribed press motion, with a position of the slide where theworkpiece can be transported without interfering with the upper diebeing defined as a feed-allowable height, and a position higher than thefeed-allowable height and highest in the press motion being defined as astand-by height, the controller being also configured to have theworkpiece transported while the slide is moving between thefeed-allowable height and the stand-by height.
 2. The press systemaccording to claim 1, wherein the controller is configured to starttransportation of the workpiece by the transportation portion while theelectric motor is decelerated.
 3. The press system according to claim 1,wherein the controller is configured to start transportation of theworkpiece by the transportation portion while the slide is moving fromthe feed-allowable height to the stand-by height.
 4. The press systemaccording to claim 2, wherein the controller starts deceleration of theelectric motor after the slide passes the feed-allowable height as theslide moves upward.
 5. The press system according to claim 1, whereinthe controller is configured to have the transportation portion completetransportation of the workpiece while the electric motor is accelerated.6. The press system according to claim 1, wherein the controller isconfigured to have the transportation portion complete transportation ofthe workpiece while the slide is moving from the stand-by height to thefeed-allowable height.
 7. The press system according to claim 5, whereinthe controller is configured to complete acceleration of the electricmotor before the slide passes the feed-allowable height as the slide ismoved downward.
 8. The press system according to claim 5, wherein thetransportation portion includes a feed completion detector configured todetect completion of transportation of the workpiece, the controllersets a monitoring position at a position higher than the feed-allowableheight and lower than the stand-by height in the upward and downwarddirection of the slide, and the controller sets the stand-by height andthe monitoring position such that the slide can be stopped at a positionhigher than the feed-allowable height when completion of transportationof the workpiece has not been detected at a time point when the slidelowered from the stand-by height reaches the monitoring position.
 9. Thepress system according to claim 1, wherein the controller has theelectric motor alternately rotate in forward and reverse directions eachtime press working is performed.
 10. The press system according to claim1, wherein the electric motor is implemented by a servo motor.